In accordance with the introduction of FD (full dimension) MIMO (multiple input multiple output) environment, 2D domain to be used by a UE can be determined/used by transmitting K (>1) number of CSI-RS (reference signal) resources to which different 2D (vertical and/or horizontal) precoding is applied to a single CSI (channel state information) process. In this case, when the UE reports a CSI-RS resource or the 2D domain to a base station, it is necessary for the UE to have a method capable of reducing UE complexity and unnecessary transmission.